#include "gwmd5.h"

using namespace gwBedrockUtil;

/***************************************************************************************************************************/
void
gwMD5Transformer::init_context(gwMD5Context* context)
{
        ///Chaining Variable
        context->buf[0] = 0x67452301;
        context->buf[1] = 0xefcdab89;
        context->buf[2] = 0x98badcfe;
        context->buf[3] = 0x10325476;

        context->bits[0] = 0;
        context->bits[1] = 0;
}

/***************************************************************************************************************************/
void
gwMD5Transformer::bytes_reserve(unsigned char* buf, unsigned int length)
{
        unsigned int t;
        do
        {
                t = (unsigned int)((unsigned)buf[3] << 8 | buf[2]) << 16 |
                    ((unsigned)buf[1] << 8 | buf[0]);
                *(unsigned int*)buf = t;
                buf += 4;
        } while (--length);
}

/***************************************************************************************************************************/
/* The four core functions - F1 is optimized somewhat */

/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))

/* This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
    ( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )

void
gwMD5Transformer::transform(unsigned int buf[4], const unsigned int in[16])
{
        register unsigned int a, b, c, d;

        a = buf[0];
        b = buf[1];
        c = buf[2];
        d = buf[3];

        MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
        MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
        MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
        MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
        MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
        MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
        MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
        MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
        MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
        MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
        MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
        MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
        MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
        MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
        MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
        MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);

        MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
        MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
        MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
        MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
        MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
        MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
        MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
        MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
        MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
        MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
        MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
        MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
        MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
        MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
        MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
        MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);

        MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
        MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
        MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
        MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
        MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
        MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
        MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
        MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
        MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
        MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
        MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
        MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
        MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
        MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
        MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
        MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);

        MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
        MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
        MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
        MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
        MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
        MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
        MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
        MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
        MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
        MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
        MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
        MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
        MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
        MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
        MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
        MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);

        buf[0] += a;
        buf[1] += b;
        buf[2] += c;
        buf[3] += d;
}

/***************************************************************************************************************************/
void
gwMD5Transformer::update_context(gwMD5Context* context, const unsigned char* content_in, unsigned int length_in)
{
          unsigned int t;

          /* Update bitcount */

          t = context->bits[0];
          if ((context->bits[0] = t + ((unsigned int)length_in << 3)) < t)
          context->bits[1]++;     /* Carry from low to high */
          context->bits[1] += length_in >> 29;

          t = (t >> 3) & 0x3f;    /* Bytes already in shsInfo->data */

          /* Handle any leading odd-sized chunks */

          if (t) {
          unsigned char *p = (unsigned char*)context->in + t;

          t = 64 - t;
          if (length_in < t) {
              memcpy(p, content_in, length_in);
              return;
          }
          memcpy(p, content_in, t);
          bytes_reserve(context->in, 16);
          transform(context->buf, (unsigned int*)context->in);
          content_in += t;
          length_in -= t;
          }
          /* Process data in 64-byte chunks */

          while (length_in >= 64) {
          memcpy(context->in, content_in, 64);
          bytes_reserve(context->in, 16);
          transform(context->buf, (unsigned int*)context->in);
          content_in += 64;
          length_in -= 64;
          }

          /* Handle any remaining bytes of data. */

          memcpy(context->in, content_in, length_in);

}

/***************************************************************************************************************************/
void
gwMD5Transformer::pad_context(gwMD5Context* context, unsigned char dig[16])
{
        unsigned count;
        unsigned char *p;

        /* Compute number of bytes mod 64 */
        count = (context->bits[0] >> 3) & 0x3F;

        /* Set the first char of padding to 0x80. This is safe since there is
           always at least one byte free */
        p = context->in + count;
        *p++ = 0x80;

        /* Bytes of padding needed to make 64 bytes */
        count = 64 - 1 - count;

        /* Pad out to 56 mod 64 */
        if (count < 8)
        {
                /* Two lots of padding: Pad the first block to 64 bytes */
                memset(p, 0, count);
                bytes_reserve(context->in, 16);
                transform(context->buf, (unsigned int*)context->in);

                /* Now fill the next block with 56 bytes */
                memset(context->in, 0, 56);
        }
        else
        {
                /* Pad block to 56 bytes */
                memset(p, 0, count - 8);
        }
        bytes_reserve(context->in, 14);

        /* Append length in bits and transform */
        ((unsigned int*)context->in)[14] = context->bits[0];
        ((unsigned int*)context->in)[15] = context->bits[1];

        transform(context->buf, (unsigned int*)context->in);
        bytes_reserve((unsigned char*)context->buf, 4);
        memcpy(dig, context->buf, 16);
}

/***************************************************************************************************************************/
std::string
gwMD5Transformer::generate(const std::string& in)
{
        gwMD5Context context;
        unsigned char ss[16];
        char buff[33] = {'\0'};
        char tmp[3]   = {'\0'};

        init_context(&context);
        update_context(&context, (const unsigned char*)in.c_str(), in.size());
        pad_context(&context, ss);

        for(int i = 0; i < 16; ++i)
        {
                sprintf(tmp,"%02X", ss[i] );
                strcat(buff,tmp);
        }

        return buff;
}
